This invention is directed to an air turning vane assembly of the type which is installed in an air duct and a method of fastening the vanes to such an assembly. It is particularly concerned with an air turning vane assembly which can be assembled in a sheet metal shop quickly by a workman using relatively simple tools.
Air turning assemblies are installed in sheet metal duct work at turns, especially right angle turns, to reduce friction loss. Since such air turning vane assemblies must fit a particular size duct, they are usually assembled at a sheet metal shop from prefabricated rails and vanes. Thus, each air vane assembly is made up of a large number of parts which have to be fastened together by a workman using dowels, screws or nails. Air turning vanes constructed in this manner are liable to work loose and to rattle after they are installed. Also, such construction is extremely labor intensive, expensive and unsatisfactory.
One attempt to solve this problem was to form slotted dimples in the rails and insert the vanes in the slots of the dimples, then flatten the protruding portions of the vanes that extend through the dimples with a hammer or twisting tool. An assembly of this type is expensive and labor intensive because it requires a careful alignment of the vanes with the slots and dimples formed in the rails and requires the bending of at least two dimples per vane at each rail to fasten the vane to the rail.
An alternate form of construction of an air turning vane assembly utilizes tabs formed in the rails which engage the vanes. Notches are formed in the rail and in the tabs adjacent each vane to provide an opening for a hammer which can be used to bend a portion of the vane over the tab into the notch to secure the vanes to the side rails. In this prior construction, the uniformity of the connection depends to a great degree on the skill of the workman being able to bend the portion of the vane over the tab without damaging the remaining portions of the side rails.
The present invention is directed to an air turning vane assembly which can be assembled by a workman using relatively simple tools to provide a uniformly effective fastening connection each time between a vane and rail.